PA 363 was first designated by the Pennsylvania Department of Highways in 1928 to run from PA 23 in Port Kennedy to PA 63 in Lansdale. Between the 1940s and the 1960s, PA 363 extended west on present-day PA 23 to end near Valley Forge. In the 1960s, the route was redirected to follow Gulph Road to US 202 in King of Prussia. By 1989, the south end of PA 363 was relocated to the US 422 interchange. The Betzwood Bridge, which had carried PA 363 over the Schuylkill River, was removed in the 1990s. The partial interchange with US 422 became a full interchange in 2015.

PA 363 continues as a two-lane undivided road past more homes as it continues to the Ridge Pike intersection. At this point, the route turns northwest onto Ridge Pike and fully enters Lower Providence Township, passing businesses as a three-lane road with a center left-turn lane. PA 363 turns northeast onto two-lane Park Avenue and runs through more residential areas. A short distance after crossing into Worcester Township, the route comes to the community of Fairview Village and crosses Germantown Pike in commercial areas.[3][4]

Upon crossing Germantown Pike, PA 363 becomes known as Valley Forge Road and continues into agricultural areas with scattered residential neighborhoods. The amount of development increases until the road comes to the junction with PA 73 (Skippack Pike) in the community of Worcester. After the PA 73 intersection, PA 363 continues past areas of housing developments to the west and farmland to the east before it reaches Morris Road. At this point, the route becomes the border between Towamencin Township to the northwest and Upper Gwynedd Township to the southeast, crossing under I-476 (Pennsylvania Turnpike Northeast Extension) along this stretch.[3][4]

The road passes through residential neighborhoods before entering commercial areas and crossing Sumneytown Pike. PA 363 heads to the southeast of North Penn High School and runs past a mix of homes and businesses as it gains a center left-turn lane on the approach to the Allentown Road junction. A short distance later, the route enters Lansdale and passes homes as a two-lane road. PA 363 reaches its northern terminus at an intersection with PA 63 in Lansdale.[3][4]

When Pennsylvania first legislated routes in 1911, present-day PA 363 was not given a number with the exception of the Ridge Pike portion, which was designated as part of Legislative Route 146.[5] In 1928, PA 363 was designated to run between PA 23 in the Port Kennedy section of Upper Merion Township and PA 63 in Lansdale. The route headed north across the Schuylkill River near the present US 422 bridge, before heading north on Trooper Road and east on Egypt Road to an intersection with US 422 (Ridge Pike). PA 363 headed west concurrent with US 422 before heading north on Park Avenue and following its current alignment north to Lansdale. At this time, the route was paved between PA 23 and the north end of the US 422 concurrency.[1] By 1930, PA 363 was rerouted to follow Trooper Road between Egypt Road and US 422. At this time, the entire length of the route was paved.[6]

By 1945, PA 363 was extended west to end at PA 23 a short distance to the east of the community of Valley Forge.[7] This portion of route was cosigned with PA 23 Truck by 1950.[8][9] PA 363 was rerouted to follow Gulph Road from Port Kennedy to US 202 in King of Prussia, with PA 23 being rerouted to follow the former PA 363 between Valley Forge and Port Kennedy, by 1967. Also by this time, the US 422 concurrency on Ridge Pike had been removed and a freeway had been built that connected PA 363 a short distance north of the Schuylkill River to the US 202 freeway on the border of Chester and Montgomery counties.[10]

By 1989, the southern terminus of PA 363 was cut back to its current location at the US 422 interchange.[11] In 1991, the Betzwood Bridge, which had carried PA 363 over the Schuylkill River, was closed because of structural issues.[12] The bridge was removed in 1995 and limited bicycle and pedestrian access to Valley Forge National Historical Park from the north, with a temporary bike path being erected on the parallel US 422 bridge.[13] There were plans to replace the Betzwood Bridge with a structure carrying two vehicle traffic lanes and a multi-use trail. These plans never advanced. Ultimately the National Park Service secured federal funding for a mixed-use trail bridge to connect the trails in the north and south sides of Valley Forge Park at the site of the old bridge. Named Sullivan's Bridge after Revolutionary War General John Sullivan, construction began on the new bridge in May 2014[14] and it opened August 19, 2016 for pedestrian and bicycle traffic.[15] In addition, improvements to the interchange between PA 363 and US 422, which will add a ramp from PA 363 to westbound US 422 and from eastbound US 422 to PA 363, started in 2013.[16] The new ramps opened to traffic on December 1, 2015.[17]